P0038 Personal Dietary Effect on Fecal Calprotectin is explained by Gut Microbiome Composition

Abstract Background Although diet is a key modifiable risk factor for Crohn’s disease (CD), the extent of individual variability in dietary effects remains poorly understood. This study integrated picture-based dietary monitoring with fecal calprotectin (FCP) measurements to investigate personalized dietary effect. We also hypothesize that personal effect was defined by gut microbiome composition. Methods We conducted a 7-week longitudinal study in healthy first-degree relatives (FDRs) of patients with CD to assess personalized dietary effects on FCP and gut microbiome dynamics. Participants recorded 3–5 daily meals using RxFood, an app that applies convolutional neural network analysis to food pictures to capture dietary composition. FCP was quantified by ELISA, and diet-FCP associations were assessed by a Mixed-Effects Bayesian network (MEBN) model. K-means clustering analysis revealed distinct, individualized patterns of FCP responses to diet. Gut microbiome profiling was performed by shotgun metagenomic sequencing and processed to genus level using HUMAnN3 pipeline. Microbiome differences across diet-FCP response clusters were assessed using Kruskal-Wallis, Wilcoxon, PCoA, and PERMANOVA. Results The study analyzed data from 23 participants, including 13,753 food items from 6,616 meals and 682 stool samples. Using an MEBN model, 55% of the dietary components showed consistent associations with FCP levels, with cholesterol positively and fiber negatively associated. The remaining dietary components displayed individual-specific effects. Clustering analysis of personalized nutrient-FCP effects revealed four distinct clusters. These clusters were associated with significant differences in gut microbiome composition, including genus-level variations (Faecalibacterium, Bacteroides, Roseburia, Ruminococcus, Collinsella) (q < 0.05) and distinct community structures (PERMANOVA, p = 0.001). Conclusion Our findings demonstrate that diet has personalized effects on FCP levels, and that these dietary response patterns are accompanied by distinct differences in gut microbiome composition. Together, these results highlight the potential for developing tailored dietary interventions to modulate intestinal inflammation and influence pathways relevant to CD risk. Conflict of interest: Dr. Shah, Ishfaq: No conflict of interest Alyssa, Alyssa: No conflict of interest Murphy, Robyn: No conflict of interest Xue, Mingyue: No conflict of interest Jingcheng, Shao: No conflict of interest Bharali, Biju: No conflict of interest Li, Qilong: No conflict of interest Dang, Cong: No conflict of interest Leibovitzh, Haim: No conflict of interest Lee, Sun-Ho: No conflict of interest Croitoru, Kenneth: No conflict of interest Turpin, Williams: Grant: Weston Family Foundation Grant: IOIBD Travel IMKASID